My buddy did the exact same thing last spring and his monstera kept dropping leaves no matter what the app said. Turns out the meter was reading just fine but he had the pot sitting right next to a heating vent, so the soil was drying out way faster than the app predicted. He moved it three feet away from the vent and stopped messing with it every day, and the thing bounced back in like a month. The apps are handy for ballpark numbers but they don't know about drafts or how much light your window actually blocks. Parlor palms are dramatic anyway, they sulk over the smallest changes and take forever to show you they're happy again. Give it a spot it likes and then leave it alone for a few weeks, that's usually the fix.